Parenteral tubing set and method of making same



Feb. 2, 1960 R. c. REIMANN ET AL 2,923,294

PARENTERAL TUBING SET AND METHOD OF MAKING SAME Filed Nov. 3, 1955 Faberi C Kai/nan Joseph ,4. O/eru'cki IN VEN TOR.$. y nm J also must be free of leaks.

States nite PARENTERAL TUBING SET AND'METHOD OF MAKING SAME Application November 3, 1955, Serial No. 544,726

6 Claims. (Cl. 123-214) This invention relates to a parenteral tubing setand a method for preparing the same and, more particularly, to a set provided with means adapted to indicate the absence of leaks therein.

The parenteral tubing sets to which our invention is applicable have essentially two uses. One use involves the conveying of fluids suitable for injection into the human body from an outside source. The seconduse involves the removal of parenteral fluids from the body for collection or other disposal. An obvious example of the second use is the collection of blood. The apparatus employed for these uses includes essentially a length of flexible tubing, the ends of which are provided with fittings, such as needles, suitable for introduction into the body and to the source or collection container, as the case may be. In some instances, the end fittings are plastic adapters constructed to be inserted into the hubs subjecting the assembled set to a temperature of about 250 F. Contamination subsequent to sterilization was attempted to be avoided by provisionof protector sleeves over the end fittings thereby insulating the interior of the tubing and fittings as well as the ensleeved exterior of the fittings from contact with unsterile objects and media.

Not only must a parenteral tubing-set be sterile'but it Should an opening exist in the wall of the flexible tubing it might permit the entry of contaminating bacteria and the like. More importantly, however, such a leak might aspirate air into the set which in turn would deliver the air into the body of the patient. Therefore, each setis tested for leaks before use.

A common method of testing currently employed is to provide one of the aforementioned protector sleeves with an unsealed end, plugging the opening formed thereby with cotton to minimize the entry of bacteria. A valve and gage-equipped air pressure line is attached to the open end of the protector sleeve and the interiorof the set is pressurized with air from about 6 psi. to 15 psi.

Failure of the set to maintain the pressure afterclosure of the valve indicates the presence of leaks .or poor connection of the various elements of the set. In the instance of some sets where even minute leaks are objectionable, i.e., small bore sets for children denominated pediatric sets, the set is submerged in water after being internally pressurized.

" It was thought that the open-ended protector also serves another purpose in that it permits air exit and entry during heat sterilization. Heat sterilization is ordinarily achieved in an autoclave wherein the steam temperature reaches about 250 F. During portions of the sterilization cycle the pressure .insideatheset is :greater than that in the autoclave, which pressure, if unrelieved, it was 2,923,294 Pate ted Fens, 1960 believed would rupture the sch-hence the apparent .need for a vented protector. I

We have found however that the above described thinking about rupture of a closed set has no basis in fact. To the contrary, we have ascertained that the flexible tubing in a closed set expands slightly to equalize the pressure differential existing when the set is being sterilized. Upon subsequent cooling, the expanded tubing does not contract, so that upon removal from the sterilizer a slightly sub-atmospheric pressure exists in the closed set.

In our invention 'we have utilizedthis discovery to provide a structure that eliminates the previously employed cumbersome andcostly testing procedure. Our invention involves the provision of a closed-ended protector in place of the normally provided vent-type protector, the closed-endedprotector being of such character as to collapse to equalize the internal and external pressures, and at the same time to provide va visual indication of the reduced pressure conditionwithinthe set and thereby its integrity.

Our invention will be described in conjunction with the accompanying drawing in which Fig. l is an elevational view depicting a conventional parenteral administration apparatus such as would utilize the tubing set of our invention; Fig. 2 is an enlarged, cross-sectional view of one end of the tubing set shown in Fig. 1 but before the protector has been removed; Fig. 3 is an enlarged, crosssectional view similar to Fig. 2 butshowing our invention as applied to a modified form of parenteral tubing set.

Referring now to the drawing and, in particular, Fig. 1, thenurneral l0 designates a parenteral solution container mounted in a mouth downward condition by means of suspending bail 11 from a suitable stand (not shown). Liquid from container 10 is permitted to flow through parenteral tubing set generally designated 12 into a human recipient (also not shown).

Parenteral tubing set 12 as depicted in Fig. 1 is seen to be composed of two interconnected conduit elements, a drip meter set generally designated 13 and a small bore tubing set, generally designated 14. Set 14 as shown has particular application in pediatric parenteral therapy as where the needle 15 is inserted into an infants scalp vein.

.In Fig. 1, set 13 is seen to include a conventional drip meter 16 inserted through a stopper (not shown) of container 10 so vasto establish an outlet conduit for the parenteral fluid contained in container 10. Mountedon the outlet portionof drip meter 16 is a length of flexible tubing 17 terminatingiin :aLuer adapter 18 inserted into tubing 17.

,Set14 also includes a length of flexible tubing, desig nated 19k, itheends of which are also provided with Luer adapters, one of which, designated numeral 20 is'reverselyrnounted to accommodate engagement with adapter 18 of set "13. The adapter provided at the opposite or discharge end of set 14 isdesignatedll and has needle 15 .removablymounted thereon. The manner of coaxially attaching adapters 2t and 21 totubing 19:0f; set 14 will be explainedby ICfr6l1CeftO .Fig-.2.

Referring now toFig. 2,"a specific-:embodiment of our invention is shown in enlarged cross-sectional view. 'As indicated above, the flexible tubing 19- of set 14is connected toadapter means designated 21. In the embodiment shown-in Fig. 2, this connection is'achieved through the use of an intermediate sleeve 22 heat sealed to tubing '19 according to the teaching of Patent'No. 2,702,036. Sleeve 22 is ensleeved over .plastic adapter 21 which is end as at 23so as to fit .into aiconventional hypodermic needle 15.

gress or egress as by heat sealing at 25.

A similar end connection and protector can be provided at the other end of tubing 19 (not shown in Fig. 2) or the other end may be provided with various types of puncturing devices known to the art. Such other puncturingdevices may take the form of the hypodermic needle shown in Fig. 3 wherein like numerals are used to denote like parts except for the addition of a prime. In Fig. 3 tubing 19' is connected to needle 15 by ensleeving tubing 19' over the hub of needle 15' and securing the connection so achieved by collar 26'. Also mounted over the hub portion of hypodermic needle 15' of is rigid protector 27'. Such a protector is generally required to prevent inadvertent puncture of a softer protector prior to actual use of the set. Ensleeved over rigid protector 27 is resilient protector 24, substantially similar to that shown in Fig. 2.

In the method of preparing the set of our invention, a length of flexible tubing 19 is secured into a larger diameter sleeve 22 by means of a four-way heat seal. Adapter 21 is then inserted into sleeve 22 and protector 23, which has been previously provided with heat seal 25, is ensleeved over adapter 21.

When the other end of tubing 19 has been provided with a similar structure (as for example the reversely mounted Luer adapter shown in Fig. l) or otherwise closed against entrance of air, the assembly is introduced into an autoclave where the set is subjected to a temperature in the range of 230-250 F. for a sufficient time to bring the set and its contained air to that temperature. During the heating-up period in the sterilizer, it appears that the pressure external to the set is less than the internal pressure so that a portion of the air within the set tends to expand. The same phenomenon apparently takes place during the cooling portion of the sterilization cycle.

Upon removal of the set from the autoclave, the walls of protector are found to be collapsed as at 28 or 28'. The drawing together of the opposite wall portionsproduces a distinctive shading or opaqueness when the set is held up to lightthereby providing a ready means for checking its integrity. By constructing protector 24 of a translucent or transparent plastic material, the above mentioned opacity is readily achieved.

It is felt that the wall portions of protector 24 collapse in preference to those of tubing 19 because of the difference in dimensions, i.e., bore and wall thickness. Tubing 19 is so sized as to be substantially not collapsible by p and extending over the length of the needle portion therethe application of atmospheric pressure when the internal 1 pressure is less than atmospheric. An example of a set produced in accordance with the teaching of our invention includes an 18 length of flexible tubing 19 con structed of polyvinyl chloride having aninternal diameter of .054" and a wall thickness of .018". Protector 24 has an unsupported length of approximately an overall length of 2%, an internal diameter of 0.180 and a wall thickness of .022".

When the dimensions of tubing 19 are increased to .140" internal diameter and .035" wall thickness the phenomenon described above is not achieved.

We have found that the collapse of protector 24 achieved by the foregoing procedure is temporary since the plastic tubing used is slightly permeable to air. Thus the visual indication achieved may disappear in about 24 hours if the degree of vacuum within the set is small. Notwithstanding the possible shortness of duration of the visual indication, which, however, is adequate for checking, it is important to note that the closed set produced in accordance with the teaching of our invention is superior to conventionally produced sets having a protector with a cotton plugged open end. The resist- 4 ance ofiered by a closed protector to the entrance of bacteria and other contaminating elements is definitely superior to that otfered by cotton.

The foregoing detailed description has been given for clearness of understanding only and no unnecessary limitations should be inferred therefrom.

We claim:

1. A parenteral tubing set comprising a length of flexible tubing, puncture means affixed to at least one end thereof, said tubing being closed at a point spaced from said puncture means, resilient protector tubing means removably mounted on said puncture means and closing the same, the said protector tubing means being so arranged and constructed as to cause a portion of said protector tubing means to collapse after the said set has been subjected to heat sterilization, whereby a visual indication of the integrity of the set is achieved.

2. A parenteral tubing set comprising a length of flexible tubing, puncture means affixed to at least one end thereof, the other end of said tubing being closed against rapid entrance of air whenever the pressure within the set is less than that external to the set, resilient protector tubing means removably mounted on said puncture means closing the same against rapid entrance of air whenever the pressure within the set is less than that external to the set, the said protector tubing means being of such a wall thickness and diameter in comparison to the wall thickness and diameter of said resilient tubing so as to cause a portion of said protector tubing means to preferentially collapse after the said set has been subjected to heat sterilization.

3. A parenteral tubing set comprising a length of flexible tubing, puncture means affixed to at least one end thereof, the other end of said tubing being provided with removable closure means closing the same, a resilient, translucent thermoplastic tube removably mounted on said puncture means, said protector tube being closed at its unmounted end by a single heat seal, the closed end of said protector tube being spaced from the unattached end of said puncture means, said protector tube being so dimensioned as contrasted to said flexible tubing as to cause opposite wall portions of said protector tube to draw together to produce an observable shading after the said set has been subjected to heat sterilization.

4. A method of producing a heat-sterilized, non-leaking-parenteral tubing set comprising: closing one end of a length of flexible tubing with a removable closure, inserting into the other end of said flexible tubing :1

non-collapsible tubular element, removably ensleeving said tubular element with a flexible, resilient, translucent closed'ended protector, said protector being so dimensioned with respect to said flexible tubing as to preferentially collapse when the pressure inside the set is less than that external to the set, heat sterilizing the set so achieved, cooling the said set, whereby a portion of said protector is collapsed to provide an' indication of the non-leaking character of said set, and thereafter visually examining said protector.

5. The method of claim 4 in which the examination is performed within a short time after cooling and within about twenty-four hours after cooling.

6. A method of detecting air leaks in parenteral tubing equipment comprising the steps of releasably closing both ends of a length of flexible tubing, one of said ends being equipped with a closure member constructed of a flexible, resilient, translucent material, said closure member being so constructed and arranged with respect to said tubing as to preferentially collapse when the pressure inside of the closed set is less than that external to the set to provide a perceptible shading in said closure member, heat sterilizing the set, cooling the set and thereafter visually examining the said closure member to ascertain the presence of a shaded portion.

(References on following page) References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Walter and Murphy: A Closed Gravity Technique for the Preservation of Whole Blood in ACD Solution Utilizing Plastic Equipment, Surgery, Gynecology and Obstetrics, vol. 94, No. 6, pp. 687-692, June 1952. (Available in Scientific Library.) 

